The general procedure for the synthesis of 2-(3-methoxyphenyl)ethanol from 3-methoxyphenylacetic acid is as follows: first, 3-methoxyphenylacetic acid (75.09 mg, 0.5 mmol), rhenium complex (7.07 mg, 0.010 mmol), and potassium tetraphenylborate (17.92 mg, 0.05 mmol) were added to dry 25 mL glass tubes equipped with stirring bars . The mixture was transferred to an autoclave and dehydrated toluene (4.0 mL) was added under argon protection. Subsequently, the argon gas in the autoclave was replaced with hydrogen, a process accomplished through a stainless steel tube connected to a hydrogen cylinder and repeated five times to ensure complete replacement. The hydrogen pressure was set to 4 MPa, and the autoclave was placed in a thermostatic bath at 180°C for 12 hours. At the end of the reaction, the autoclave was cooled to room temperature and the hydrogen pressure was slowly released. After removing the solvent, the reaction products were analyzed by 1H NMR using homotrimethylbenzene (60.1 mg, 0.5 mmol) as an internal standard, and the yields of 2-(3-methoxyphenyl)ethanol and 3-methoxyphenylacetic acid were obtained as 98% and 1%, respectively. For different substrates and hydrogenation conditions, the specific conditions were adjusted with reference to those in Tables 7-9, where entries 19-26 used tetrahydrofuran (THF) as solvent. The experimental results are detailed in Tables 7 to 9.
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